Summary: The candidate is a successful medical education researcher who seeks to gain additional research training in pediatric health services research (HSR) in order to build on his past work of measuring trainee performance. The proposed training plan incorporates a Master's of Science in Clinical Research, completing advanced courses in biostatistics;data management;regression;and courses in outcomes research, focusing on archival clinical data, billing data, and qualitative research methods. His institution, Department, and Division have strong track records of supporting generalist researchers. The proposal has the overall aim of the candidate gaining pediatric HSR skills by evaluating the frequencies, types, and patterns of ambulatory medication prescribing errors in children. The first aim is a validation of an algorhythmic approach to assigning weights to pediatric patients - a crucial competent of research that seeks to determine medication dosing errors. Aim 2 constitutes a comprehensive evaluation of one state's Medicaid data to define and determine the frequency of prescribing errors for children. Aim 3 determines provider and patient characteristics associated with prescribing errors, allowing determination of potential "at risk" patients or provider profiles and laying the groundwork for future interventions to reduce prescribing errors. Aim 4 will determine the potential for ambulatory electronic medical record systems that contain prescribing modules to reduce prescribing errors. Aim 5 is an in-depth evaluation of one clinic's prescribing errors in order to determine the relative contributions of providers and pharmacies to erroneous prescriptions received by patients. The investigator has proposed a training program and research plan that will allow him to become an independent pediatric health services researcher while completing research that will lead to improved quality of medical care for vulnerable populations (low-income children and minority children). The immediate goal is to produce 8 manuscripts from the proposal. Long-term, the candidate will become one of the few researchers trained in both medical education and pediatric health services research. Relevance: This project meets the goals of improving patient safety set forth by the Institute of Medicine and is directly applicable to the Agency for Healthcare Research and Quality's mission "to improve the quality, safety, efficiency, and effectiveness of health care for all Americans."